The invention is based on hand power tool.
In order to be able to advantageously connect an inserted tool to a drive shaft of a machine tool by means of a tool holding fixture, it is known to affix the drive shaft to a locking device.
For right angle grinders, a locking device is known that has a locking bolt, which is guided in a housing so that it is rotationally fixed in relation to the drive shaft and which, by means of an actuating button, can be brought into engagement with a gearing that is non-rotatably connected to the drive shaft.
In addition, EP 0 904 896 A2 has disclosed a grinding machine tool holding fixture for a manually operated right angle grinding machine. The right angle grinding machine has a drive shaft, which has a thread oriented toward the tool.
The grinding machine tool holding fixture has a driver and a retaining nut. In order to install a grinding wheel, the driver is slid with a mounting opening onto a collar of the drive shaft and by means of the retaining nut, is clamped in a frictionally engaging manner to a supporting surface of the drive shaft. Oriented toward the tool and extending in the axial direction, the driver has a collar that has recesses on its outer circumference, on two radially opposing sides, which extend axially to a base of the collar. A groove extends on the outer circumference of the collar, counter to the drive direction of the drive shaft, starting from each of the recesses. The grooves are closed counter to the drive direction of the drive shaft and taper axially starting from the recesses, counter to the drive direction of the drive shaft.
The grinding wheel has a hub with a mounting opening, which contains two opposing tabs pointing radially inward. The tabs can be inserted axially into the recesses and then introduced circumferentially into the grooves, counter to the drive direction. By means of the tabs in the grooves, the grinding wheel is fixed in a form-fitting manner in the axial direction and is fixed in a frictionally-engaging manner by the tapering contour of the grooves. During operation, the frictional engagement increases due to the reaction forces acting on the grinding wheel, which act counter to the drive direction.
In order to prevent the grinding wheel from coming off when the driver is braking the drive shaft, in the vicinity of a recess on the circumference of the collar, a stopper is provided, which is supported so that it can move in the axial direction in an opening. In an operating position with the grinding wheel pointing downward, the stopper is axially deflected toward the grinding wheel by the force of gravity, closes the groove in the direction of the recess, and prevents the tabs disposed in the groove from moving in the drive direction of the drive shaft.